Which system specifically utilizes Alpha and Beta ranges to manage propeller action?

Which system specifically utilizes Alpha and Beta ranges to manage propeller action?

• A. Reversible-pitch turboprop propellers
• B. Hydraulic landing gear
• C. Air conditioning pack
• D. Fuel control unit

Answer: (A)

Alpha and Beta ranges describe how a reversible-pitch turboprop controls blade angle to manage thrust. In the Alpha range, the propeller governor maintains a chosen rotational speed by adjusting the blade pitch for normal forward thrust during flight. When the system is placed in the Beta range, the pitch mechanism shifts to a configuration that enables reverse thrust or braking on the ground, allowing deceleration after touchdown and precise control at low speeds. This dual-range setup is specific to reversible-pitch turboprops, where the ability to switch between forward thrust and reverse thrust is built into the propeller control system. The other options involve systems (hydraulic gear actuation, environmental control, and fuel delivery) that do not use Alpha/Beta ranges to govern propeller action.

Alpha and Beta ranges describe how a reversible-pitch turboprop controls blade angle to manage thrust. In the Alpha range, the propeller governor maintains a chosen rotational speed by adjusting the blade pitch for normal forward thrust during flight. When the system is placed in the Beta range, the pitch mechanism shifts to a configuration that enables reverse thrust or braking on the ground, allowing deceleration after touchdown and precise control at low speeds. This dual-range setup is specific to reversible-pitch turboprops, where the ability to switch between forward thrust and reverse thrust is built into the propeller control system. The other options involve systems (hydraulic gear actuation, environmental control, and fuel delivery) that do not use Alpha/Beta ranges to govern propeller action.